Amorphous Ru nanoclusters onto Co‐doped 1D carbon nanocages enables efficient hydrogen evolution catalysis

The development of high-performance electrocatalysts for hydrogen evolution reaction(HER)is of great significance for green,sustainable,and renewable energy conversion.Herein,we report the synthesis of amorphous Ru clusters on Co-doped defect-rich hollow carbon nanocage(a-Ru@Co-DHC)as an efficient electrocatalyst for HER in the basic media.Due to the advantages such as high surface area,rich edge defect,atomic Co doping and amorphous Ru clusters,the as-made a-Ru@Co-DHC displays an efficient HER performance with a near-zero onset overpotential,a low Tafel slope(62 mV dec^(−1)),a low overpotential of 40 mV at 10 mA cm^(−2) and high stability,outperforming the commercial Ru nanocrystal/C,commercial Pt/C,and other reported Ru-based catalysts.This work provides a new insight into designing new metal doped carbon nanocages catalysts supported by amorphous nanoclusters for achieving the enhanced electrocatalysis.

Rh-Cu alloy nano-dendrites with enhanced electrocatalytic ethanol oxidation activity

The application of direct ethanol fuel cell(DEFC)has been bottlenecked by the sluggish ethanol oxidation reaction(EOR).Efficient electrocatalysts for the C-C bond cleavage are essential to promote EOR with high efficiency and C1 selectivity.Here,we prepared Rh-Cu alloy nano-dendrites(RhCu NDs)with abundant surface steps through controlled co-reduction,which exhibited significantly enhanced activity and C1 selectivity(0.47 m A cm_((ECSA))^(-2),472.4 mA mg_(Rh)^(-1),and 38.9%)than Rh NDs(0.32 mA cm((ECSA))-2,322.1 mA mgRh-1,and 21.4%)and commercially available Rh/C(0.18 mA cm_((ECSA))^(-2),265.4 mA mg_(Rh)^(-1),and 14.9%).Theoretical calculations and CO-stripping experiments revealed that alloying with Cu could modulate the surface electronic structures of Rh to resist CO-poisoning while strengthening ethanol adsorption.In situ Fourier transform infrared spectroscopy(FTIR)indicated that the surface steps on RhCu NDs further promoted the C-C bond cleavage to increase the C1 selectivity.Therefore,optimizing the surface geometric and electronic structures of nanocrystals by rational composition and morphology control can provide a promising strategy for developing practical DEFC devices.

A Boron-based Adhesion Aid for Efficient Bonding of Silicone Rubber and Epoxy Resin

We improved the adhesion between silicon based insulating materials and epoxy resin composites by adding the adhesion promoter cycloborosiloxane(BSi,cyclo-1,3,3,5,7,7-hexaphenyl-1,5-diboro-3,7-disiloxane).The experimental results show that the addition of BSi in the silicone rubber(SR)system significantly increases the tensile shear strength between BSi and epoxy resin(EP),reaching 309%of the original value.On this basis,the mechanism of BSi to enhance the adhesion effect was discussed.The electron deficient B in BSi attracted the electron rich N and O in EP to enhance the chemical interaction,combined with the interfacial migration behavior in the curing process,to improve the adhesion strength.This study provides the design and synthesis ideas of adhesive aids,and a reference for further exploring the interface mechanism of epoxy resin matrix composites.

多电子电池体系的关键技术与工程发展

1.Introduction:Opportunities for new energy systems With the rapid development of next-generation technologies-including the Internet,information technology,quantum technology,micro-nano technology,big data,and artificial intelligence-human civilization is rapidly moving toward an intelligent era(following the electrification and information age).

Atomic regulations of single atom from metal-organic framework derived carbon for advanced water treatment

Single atom(SA)-embedded nitrogen-doped carbon has shown great potential in environmental remediation.Nowadays,engineered nanomaterials(ENMs)have attracted great research interests in recent years.Metal-organic framework(MOF)derived SAs show the advantages of tunable topology and averaged separated active sites.SAs bridge the gap between homogeneous and heterogeneous catalysts.The reaction efficiency can be significantly improved by designing the MOFs derived from carbon and SAs.In this review,the research advanced in MOFs-derived carbon and SAs in advanced oxidation process(AOP)in water were summarized.Major strategies to fabricate the SAs derived from MOFs were discussed,including the mixed/single metal strategy,metal-containing linker strategy,pore confinement strategy,thermal diffusion strategy,and pyrolysis MOFs with bulk metals.Advanced characterization technologies have been introduced,including electron microscopy and spectroscopic methods.To explain the catalytic mechanism for various applications,the relationship between the performance and the atomic configuration was systematically discussed.Recent applications of the MOFs derived from carbon and SAs have been summarized.A series of the latest work on effectively removing pollutants by SAs are also listed.Based on the fundamental knowledge and recent practical application of MOFs-derived carbon and SAs,some perspectives on the further directions were presented.This review offers guidance for applying novel engineered nanomaterials in the water treatment field.

Ru-doped functional porous materials for electrocatalytic water splitting

Electrolytic water splitting(EWS)is an attractive and promising technique for the production of hydrogen energy.Nevertheless,the sluggish kinetic rate of hydrogen/oxygen evolution reactions leads to a high overpotential and low energy efficiency.Up to date,Pt/Ir-based nanocatalysts have become the state-of-the-art EWS catalysts,but disadvantages such as high cost and low earth abundance greatly limit their applications in EWS devices.As an attractive candidate for the Pt/Ir catalysts,series of Ru-based nanomaterials have aroused much attention for their low price,Pt-like hydrogen bond strength,and high EWS activity.In particular,Ru-doped functional porous materials have been becoming one of the most representative EWS catalysts,which can not only achieve the dispersion and adjustment for active Ru sites,but also simultaneously solve the problems of mass transfer and catalytic conversion in EWS.In this review,the design and preparation strategies of Ru-doped functional porous materials toward EWS in recent years are summarized,including Ru-doped metal organic frameworks(MOFs),Ru-doped porous organic polymers(POPs),and their derivatives.Meanwhile,detailed structure–activity relationships induced by the tuned geometric/electronic structures of Ru-doped functional porous materials are further depicted in this review.Last but not least,the challenges and perspectives of Ru-doped functional porous materials catalysts are reasonably proposed to provide fresh ideas for the design of Ru-based EWS catalysts.

Coordination-environment regulation of atomic Co-Mn dual-sites for efficient oxygen reduction reaction

Precisely designing atomic metal-nitrogen-carbon(M-N-C)catalysts with asymmetric diatomic configurations and studying their structure–activity relationships for oxygen reduction reaction(ORR)are important for zinc-air batteries(ZABs).Herein,a dualatomic-site catalyst(DASC)with CoN_(3)S-MnN_(2)S_(2) configuration was prepared for the cathodes of ZABs.Compared with Co-N-C(Mn-free)and CoMn-N-C(S-free doping),CoMn-N/S-C exhibits excellent half-wave potential(0.883 V)and turnover frequency(1.54 e·s^(−1)·site^(−1)),surpassing most of the reported state-of-the-art Pt-free ORR catalysts.The CoMn-N/S-C-based ZABs achieve extremely high specific capacity(959 mAh·g^(−1))and good stability(350 h@5 mA·cm^(−2)).Density functional theory(DFT)calculation shows that the introduction of Mn and S can break the electron configuration symmetry of the original Co 3d orbital,lower the dband center of the Co site,and optimize the desorption behavior of*OH intermediate,thereby increasing the ORR activity.

Synergy enhancement of Co single atoms and asymmetric subnanoclusters for Fenton-like activation

As a new water treatment technology,Fenton-like reaction has great potential.In this study,we successfully prepared an excellent Fenton-like catalyst,which is composed of cobalt monoatoms and asymmetric subnanoclusters(labeled CoSA/Clu-C_(2)N),and exhibits excellent peroxymonosulfate(PMS)activation reactivity.By directly comparing the catalytic properties of CoSA-C_(2)N and CoSA/Clu-C_(2)N,the synergistic effects of coasymmetric Co subclusters and Co atoms on the activation of PMS and degradation of organic micropollutants were investigated.The results showed that CoSA/Clu-C_(2)N had higher degradation rates of carbamazepine(CBZ),antipyrine(AT)and chlorobenzoic acid(CA)when combined with active oxidant PMS.The cyclic frequency of CBZ was 5.4 min^(-1),which was twice as high as the catalytic constant of CoSA-C_(2)N(2.4 min^(-1)).The results show that CoSA/Clu-C_(2)N cobalt subnanoclusters and cobalt single atom can synergistically improve the catalytic performance of activated PMS oxidation of micropollutants in water.In addition,electron paramagnetic resonance(EPR)technology has proved that the introduction of Co subnano clusters in CoSA/Clu-C_(2)N is conducive to the production of singlet oxygen(1O_(2)),thereby improving the efficiency of pollutant oxidation.This work lays a solid foundation for the future design of advanced multifunctional catalysts by carefully regulating and combining monmetallic atoms and metal subnanoclusters.

Precisely modulating covalent and coordination bonds in the porous network for highly selective metal ion extraction

Scandium(Sc)is recognized as a“strategic”and“critical”element by several countries,including the U.S.and Russia,owing to its wide range of applications in high-tech fields such as superconductivity,alloys,lasers,nuclear energy,and aerospace[1].

Synergizing high valence metal sites and amorphous/crystalline interfaces in electrochemical reconstructed CoFeOOH heterostructure enables efficient oxygen evolution reaction

Cobalt hydroxide nanosheet is among the most popular oxygen evolution reaction(OER)catalyst yet still suffers from sluggish catalytic kinetics,limited activity,and poor stability.Here,an efficient in situ electrochemical reconstructed CoFe-hydroxides derived OER electrocatalyst was reported.The introduction of Fe promoted the transformation of Co^(2+)into Co^(3+)in CoFehydroxides nanosheet,along with the formation of abundant amorphous/crystalline interfaces.Thanks for the retained nanosheet microstructure,high valence Co^(3+)and Fe^(3+)species,and the amorphous/crystalline heterostructure interfaces,the as-designed electrochemical reconstructed CoFeOOH nanosheet/Ni foam(CoFeOOHNS/NF)electrode delivers 100 mA·cm^(−2) in alkaline at an overpotential of 275 mV and can stably electrocatalyze water oxidation for at least 35 h at 100 mA·cm^(−2).Meanwhile,the alkaline full water splitting electrolyzer achieves a current density of 10 mA·cm^(−2) only at 1.522 V for CoFeOOHNS/NF‖Pt/C/NF,which is much lower than that of Ru/C/NF‖Pt/C/NF(1.655 V@10 mA·cm^(−2)).This work paves the way for in-situ synergetic modification engineering of electrochemical active components.

Heterogeneous assembling 3D free-standing Co@carbon membrane enabling efficient fluid and flexible zinc-air batteries

Developing an efficient,interface-rich,and free-standing non-noble-metal electrocatalyst is vital for the flexible zinc-air batteries(ZABs).Herein,a three-dimensional(3D)heterogeneous carbon-based flexible membrane was assembled by Co@carbon nanosheets/carbon nanotubes and hollow carbon nanofiber(Co@NS/CNT-CNF)as an efficient oxygen reduction reaction(ORR)catalyst with a positive half-wave potential of 0.846 V and a small Tafel slope of 79 mV·dec^(-1).Meanwhile,the Co@NS/CNT-CNF electrode also exhibits excellent open-circuit voltage,peak power density,and long-time cycling stability in liquid-state ZABs(1.605 V,163 mW·cm^(-2),and 400 h)and flexible ZABs under flat/bending condition(1.47 V,102 mW·cm^(-2),and 80 h).Such heterogeneous flexible membrane architecture not only optimizes the electrolyte infiltration,but also provides capacious possibility for O_(2)and electrolyte transfer.Meanwhile,work-function analyses coupled with density functional theory(DFT)results demonstrate that the electron transfer capability and metal-support interaction can be well optimized in the obtained Co@NS/CNT-CNF catalyst.

Metal-organic frameworks:Synthetic methods for industrial production

Metal-organic frameworks(MOFs),which are constructed by metal ions or clusters with organic ligands,have shown great potential in gas storage and separation,luminescence,catalysis,drug delivery,sensing,so on.More than 20,000 MOFs have been reported by adjusting the composition and reaction conditions,most of them were synthesized by hydrothermal or solvothermal methods.The conventional solvothermal methods are favorable for the slow crystallization of MOFs to obtain single crystals or highly crystalline powders,which are suitable for the structure analysis.However,their harsh synthesis conditions,long reaction time,difficulty in continuous synthesis limit their scale-up in industrial production and application.Meanwhile,shaping or processing is also required to bring MOF crystals and powders into the market.Therefore,this review demonstrates the crystallization mechanisms of MOFs to understand how the synthetic parameters affect the final products.Additionally,a variety of promising synthetic routes which can be used for large scale synthesis were reviewed in details.Lastly,the prospects of MOF shaping and processing are provided to promote their industrial application.

Sealing functional ionic liquids in conjugated microporous polymer membrane by solvent-assisted micropore tightening

Porous organic polymers hold great promise for molecular sieving membrane separation.Although the inclusion of functional ionic liquid(IL)in the pores offers a facile way to manipulate their separation properties,the IL leaching during the separation process is difficult to avoid.Herein,we report a strategy to in-situ encapsulate ILs into the micropores of the conjugated microporous polymer membrane via a 6-min electropolymerization and further seal the aperture of the pores to prevent ILs leaching by solvent-assisted micropore tightening(SAMT).Upon screening the binding energy between different ILs and gas molecules,two ILs were selected to be incorporated into the membrane for CO_(2)/CH_(4) and O_(2)/N_(2) gas separations.The resultant separation performances surpass the 2008 Robeson upper bound.Notably,the ILs can be locked in the micropores by a facile high surface tension solvent treatment process to improve their separation stability,as evidenced by a 7-day continuous test.This simple and controllable process not only enables efficient and steady separation performance but also provides an effective strategy for confining and sealing functional guest molecules in the porous solids for various applications.

Multi-twinned gold nanoparticles with tensile surface steps for efficient electrocatalytic CO_(2) reduction

CO_(2) reduction reactions(CO_(2)RR) powered by renewable electricity can directly convert CO_(2) to hydrocarbons and fix the intermittent sustainable energy in portable chemical fuels. It is of great importance to develop advanced catalysts that can boost CO_(2)RR with high activity, selectivity, and efficiency at low overpotentials. Here, we report the solution synthesis using H_(2)O_(2) to modify the surface structures of gold multi-twinned nanoparticles(AuMPs) and create tensile surface steps. Calculations predicted significantly enhanced CO_(2) adsorption and boosted CO_(2)RR capabilities with inhibited hydrogen evolution reaction activity for the tensile surface steps with modified electronic structure. The H_(2)O_(2)-treated AuMPs with surface steps and 3.83% tensile lattices showed much higher activity and selectivity at lower overpotentials for CO_(2)RR than pristine gold nanoparticles.The CO-production current density reached about 98 mA cm^(-2) with a Faradaic efficiency of 95.7% at -0.30 V versus reversible hydrogen electrode in the flow cell, showing a half-cell energy efficiency as high as ~83%. Our strategy represents a rational catalyst design by engineering the surface structures of metal nanoparticles and may find more applicability in future electrocatalysis.

Strategies in constructing covalent organic framework membranes for molecular sieving

Membrane separation has emerged as one of the most economically and environmentally friendly technologies because of its low energy consumption,small footprint,and simple operation[1].

Experimental and numerical efforts to improve oxygen mass transport in porous catalyst layer of proton exchange membrane fuel cells

The effective management of oxygen transport resistance(OTR)within the cathode catalyst layer(CCL)is crucial for achieving a high catalyst performance at low platinum(Pt)loading.Over the past two decades,significant advancements have been made in the development of various high active platinum-based catalysts,aiming at enhancing oxygen mass transport and the oxygen reduction reaction(ORR).However,experimental investigations of transport processes in porous media are often computational costs and restrained by limitations in in-situ measurement capabilities,as well as spatial and temporal resolution.Fortunately,numerical simulation provides a valuable alternative for unveiling the intricate relationship between local transport properties and overall cell performance that remain unresolved or uncoupled through experimental approach.In this review,we elucidate the primary experimental and numerical efforts undertaken to improve OTR.We consolidate the available literature on OTR values and perform a quantitative comparison of the effectiveness of different strategies in mitigating OTR.Furthermore,we analyze the intrinsic limitations and challenges associated with current experimental and numerical methods.Finally,we outline future prospect for advancements in both experimental techniques and modelling methods.

Application of metal-based catalysts for Fenton reaction: from homogeneous to heterogeneous, from nanocrystals to single atom

Nowadays, increasing emissions of hazardous chemicals cause serious environmental pollution. The advanced oxidation processes (AOPs), which produce numbers of reactive oxygen species (ROS), are one of the most widely used technologies for degrading refractory pollutants in aqueous phase. Among these, Fenton reaction including both homogeneous and heterogeneous processes, has received increasing attention for water treatment. In this review, various nanomaterials with different size such as nanocrystals, nanoparticles (e.g., iron-based minerals, bimetallic oxides, zero-valent iron, quantum dots) and metal-based single atom catalysts (SACs) applied in homogeneous and heterogeneous Fenton reactions, as well as the corresponding catalytic mechanisms will be systematically summarized. Several factors including the morphology, chemical composition, geometric/electronic structures influence the catalytical behavior simultaneously. Here, the recent research advancement including the advantages and further challenges in homogeneous and heterogeneous Fenton system will be introduced in detail. Furthermore, developments for different nanomaterials, from nanocrystals, nanoparticles (minerals, bimetallic oxides represented by Fe-based catalysts, and nanosized zero valent iron materials) to SACs will be discussed. Some representative catalysts for Fenton reaction and their applications will be presented. In addition, commonly-used supports (e.g., graphene oxide, g-C3N4, and carbon nanotubes) and metal-organic frameworks (MOFs)/derivatives and metal-support interaction for improving Fenton-like performance will be introduced. Finally, different types of catalysts for Fenton reaction are compared and their practical application and operational costs are summarized.

Selective oxidation of emerging organic contaminants in heterogeneous Fenton-like systems

Heterogeneous Fenton-like reaction shows great potential for eliminating organic substances (e.g. emerging organic contaminants (EOCs)) in water, which has been widely explored in recent decades. However, the catalytic mechanisms reported in current studies are extremely complicated because multiple mechanisms coexist and contribute to the removal efficiencies. Most importantly, heterogeneous systems show selective oxidation properties, which are crucial for improving the efficiencies in the catalytic elimination of organic substances. Thus, this critical review summarizes and compares the diverse existing mechanisms (non-radical and radical pathways) in heterogeneous catalytic processes based on recent studies. The typical oxidation mechanisms during selective advanced oxidation of EOCs were systematically discussed based on the following sections, including the selective adsorption and generation of reactive oxygen species (ROS) in photo/electron-Fenton and Fenton-like systems. Moreover, the non-radical pathways are discussed in depth by the singlet oxygen, high-valent metal-oxo, electron transfer process, etc. Moreover, the direct oxidative transfer process for the removal of EOCs was introduced in recent studies. Finally, the cost, feasibility as well as the sustainability of heterogeneous Fenton-like catalysts are summarized. This review offers useful guidance for developing suitable strategies to develop materials for decomposing the organic substrates.

Three-dimensional electrically conductive–hydrophobic layer for stable Zn metal anodes

The interrelated side reactions and dendrites growth severely destabilize the electrode/electrolyte interfaces,resulting in the difficult application of aqueous Zn ion batteries(AZIBs).Hydrophobic protective layer possesses natural inhibition ability for side reactions.However,the conventional protective layer with plane structure is difficult to attain joint regulation of side reaction and Zn nucleation.Herein,a novel three-dimensional(3D)electrically conductive and hydrophobic(3DECH)interface is elaborated to enable stable Zn anode.The as-prepared 3DECHinterface presents a uniform 3Dmorphologywith hydrophobic property,large specific surface area,abundant zincophilic sites,and excellent electroconductivity.Therefore,the 3DECH interface achieves uniform nucleation and dendrite-free deposition from synergetic benefits:(1)increased nucleation sites and reduced local current density through the special 3D structure and(2)uniform electric potential distribution and rapid Zn^(2+)transport due to the electroconductive alloy chemistry,thus coupling the hydrophobic property to obtain a highly reversible Zn anode.Consequently,the modified anode achieves a superior coulombic efficiency of 99.88%over 3500 cycles,and the pouch cells using modified anode and LiMn_(2)O_(4)(LMO)cathode retain a capacity of 84 mAh g^(−1)after 700 cycles at a reasonable depth discharge of 36%,without dendrite piercing and“dead Zn.”